1. Field of the Invention
The present invention relates to a substrate processing apparatus and a substrate processing method horizontally holding a substrate such as a semiconductor wafer, a glass substrate for a liquid crystal display, a glass substrate for a plasma display, a substrate for a photomask or a substrate for an optical disk (hereinafter simply referred to as a xe2x80x9csubstratexe2x80x9d) and rotating the same about a vertical axis for supplying a processing solution such as an etching solution, a developer or a detergent to the lower surface of the substrate and processing the substrate.
2. Description of the Background Art
When a processing solution such as an etching solution is supplied to the lower surface of a substrate such as a semiconductor wafer horizontally rotated about a vertical axis, mist of the processing solution scattered during the processing may reach the upper surface of the substrate to adhere thereto or the processing solution supplied to the lower surface of the substrate may reach the upper surface of the substrate from the peripheral edge thereof. In order to solve this problem, generally employed is a substrate processing apparatus approaching a blocking member to the upper surface of the substrate for defining a narrow space between the upper surface of the substrate and the blocking member and introducing inert gas such as nitrogen gas into the space thereby preventing the mist of the processing solution or the processing solution from reaching the upper surface of the substrate.
FIG. 14 is a model diagram schematically showing the structure of a principal part of an exemplary conventional substrate processing apparatus having the aforementioned structure. A substrate W is positioned by a plurality of, e.g., three support pins 502 provided on a rotary base member 501, to be horizontally supported. The rotary base member 501, fixed to the upper end of a rotary spindle 503 rotatably supported and rotated about a vertical axis by a motor (not shown), is rotated while holding the substrate W. A blocking member 504 consisting of a circular plate equivalent in size to the substrate W is arranged above the rotary base member 501, mounted on a suspension arm 505 and horizontally held. The suspension arm 505 is vertically movably supported to be capable of approaching the blocking member 504 to the substrate W and upwardly separating the former from the latter. A gas outlet 506 is provided on the central portion of the blocking member 504 for injecting inert gas such as nitrogen gas toward the upper surface of the substrate W. The suspension arm 505 is formed on its axial portion with a gas introduction passage 507, communicating with the gas outlet 506, connected to a gas supply pipe (not shown).
A processing solution nozzle (not shown) is arranged under the rotary base member 501 for supplying a processing solution such as an etching solution, a developer or a detergent to the lower surface of the substrate W in response to the contents of processing. A cup is vertically movably arranged around the rotary base member 501 for preventing the processing solution from scattering, and a discharge/exhaust pipe is provided on the bottom portion of this cap for discharging the processing solution recovered in the cup from the substrate processing apparatus and exhausting the cup.
In order to process the substrate W in the substrate processing apparatus having the aforementioned structure, the blocking member 504 is approached to the substrate W supported by the support pins 502 provided on the rotary base member 501 for rotating the substrate W and supplying the processing solution to the lower surface of the substrate W. At this time, the inert gas is injected toward the upper surface of the substrate W from the gas outlet 506 of the blocking member 504 to be introduced into and purge the space between the upper surface of the substrate W and the blocking member 504. The inert gas introduced into the space between the substrate W and the blocking member 504 flows toward the peripheral edge of the substrate W, and is injected outward from the peripheral edge of the substrate W. Therefore, mist of the processing solution scattered from the peripheral edge of the substrate W is forced back by the flow of the inert gas outwardly injected from the peripheral edge of the substrate W not to penetrate into the space between the substrate W and the blocking member 504, and the processing solution supplied to the lower surface of the substrate W is prevented by the flow of the inert gas from reaching the upper surface of the substrate W from the peripheral edge of the substrate W.
In the aforementioned substrate processing apparatus approaching the blocking member 504 to the upper surface of the substrate W for purging the space between the substrate W and the blocking member 504 by introducing the nitrogen gas, the blocking member 504 must be approached to the upper surface of the substrate W as close as possible in order to effectively prevent the scattered mist and the processing solution from reaching the upper surface of the substrate W. However, the distance capable of approaching the blocking member 504 to the upper surface of the substrate W without coming into contact with the rotated substrate W is limited due to mechanical accuracy of the blocking member 504. In the structure approaching the blocking member 504 to the upper surface of the substrate W, therefore, the mist of the processing solution or the processing solution cannot necessarily be sufficiently prevented from reaching the upper surface of the substrate W.
The present invention is directed to a substrate processing apparatus supporting a substrate by Bernoulli effect and supplying a processing solution to the lower surface of the substrate thereby processing the substrate.
The substrate processing apparatus according to the present invention, supplying a processing solution to a substrate for performing prescribed processing, comprises a proximity suction member downwardly and outwardly injecting gas toward the overall peripheral edge of the upper surface of the substrate for sucking the substrate in a proximity state by Bernoulli effect, a rotating/driving part rotating the substrate sucked by the proximity suction member in the proximity state, and a processing solution supply part supplying the processing solution to a lower surface of the substrate rotated in the state sucked by the proximity suction member in the proximity state.
The proximity suction member sucks the substrate in the proximity state due to the Bernoulli effect for rotating the substrate, supplying the processing solution to the lower surface of the substrate and processing the substrate, thereby preventing mist of the processing solution scattered from the peripheral edge from reaching the upper surface of the substrate and adhering thereto or preventing the processing solution supplied to the lower surface of the substrate from reaching the upper surface from the peripheral edge of the substrate.
According to a preferred embodiment of the present invention, the proximity suction member comprises a support surface injecting gas from a plurality of holes thereby sucking/supporting the substrate through Bernoulli effect while setting the maximum width of each of the plurality of holes to not more than 2 mm in a section perpendicular to the direction of formation of the holes, and a passage guiding the gas to the plurality of holes.
The substrate can be properly sucked and supported.
According to another preferred embodiment of the present invention, the substrate processing apparatus further comprises a plurality of contact members arranged on the outer periphery of the substrate sucked by the proximity suction member in the proximity state, and the rotating/driving part rotates the plurality of contact members in a plane parallel to a support surface of the proximity suction member injecting the gas thereby sucking the substrate through Bernoulli effect, for at least partially bringing the plurality of contact members into contact with the substrate substantially in the peripheral direction thereof and rotating the substrate.
The substrate and the proximity suction member can be approached to each other through a simple structure for properly controlling the atmosphere on the upper surface of the substrate and preventing the processing solution scattered from the substrate from adhering to the upper surface after being splashed.
The present invention is also directed to a substrate processing method supporting a substrate by Bernoulli effect and supplying a processing solution to the lower surface of the substrate thereby processing the substrate.
Accordingly, an object of the present invention is to reliably prevent mist of a processing solution or the processing solution from reaching the upper surface of a substrate when rotating the substrate and supplying the processing solution to the lower surface of the substrate for processing the substrate.
The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.